1. Field of the Invention
The present invention relates to a flexible membrane inflating structural body such as a flexible membrane dam, which is provided on a bed of a waterway and is used as a dam (or a weir or a barrage), a wave absorbing dike, or the like, and further relates to a mounting metal fitting used in the flexible membrane inflating structural body to mount a flexible membrane onto a structure.
2. Description of the Related Art
For example, a flexible membrane dam used for a river is constructed in such a manner that a portion of a flexible membrane in the vicinity of an outer peripheral edge thereof, which flexible membrane is formed as an elongated planar sheet by vulcanization and integrally with an elastic body such as rubber, is mounted onto a structure (for example, a river bed and the side slopes thereof) by using a mounting metal fitting. This flexible membrane dam functions in a state in which it is expanded into a three-dimensional configuration by air being supplied to an interior of the flexible membrane.
A conventional mounting metal fitting used for a flexible membrane weir will be hereinafter described with reference to FIGS. 15 to 18.
A conventional mounting metal fitting 100 shown in FIG. 15 is comprised of a lower pressing metal fitting 104 provided in a lower structure 102 such as concrete, and an upper pressing metal fitting 110 which, together with the lower pressing metal fitting 104, sandwiches flexible membranes 106 and 108. Portions of the flexible membranes 106 and 108 in the vicinities of the outer peripheral edges thereof are fixed between the lower pressing metal fitting 104 and the upper pressing metal fitting 110 by fastening a nut 114 which is screwed on an anchor bolt 112 provided at the lower structure 102.
Convex portions 116 are formed in the lower pressing metal fitting 104 at both sides of the anchor bolt 112 in the transverse direction of the lower pressing metal fitting 104. Convex portions 118 are formed in the upper pressing metal fitting 110 at both sides of the anchor bolt 112 in the transverse direction of the upper pressing metal fitting 110. A convex portion 119 is formed in the upper pressing metal fitting 110 at the center thereof in the transverse direction. The flexible membranes 106 and 108 are bent by the convex portions 116, the convex portions 118, and the convex portion 119.
A conventional mounting metal fitting 120 shown in FIG. 16 includes a lower pressing metal fitting 122 and an upper pressing metal fitting 124. By screwing a bolt 128 into an anchor 126 embedded in the lower structure 102, portions of the flexible membranes 106 and 108 in the vicinities of the outer peripheral edges thereof are fixed between the lower pressing metal fitting 122 and the upper pressing metal fitting 124.
A convex portion 130 formed by a round bar is fixed to the lower pressing metal fitting 122 at a position further toward the main body of the flexible membrane weir than the bolt 128 (i.e., at the side of the bolt 128 in the direction opposite to the direction indicated by arrow E). A convex portion 132 is formed in the upper pressing metal fitting 124 at a position further toward the main body of the flexible membrane weir than the convex portion 130. The flexible membranes 106 and 108 are held in a state of being bent by the convex portion 130 and the convex portion 132.
In addition to the mounting metal fitting 100 and the mounting metal fitting 120, there is also a mounting metal fitting 140 shown in FIG. 17. The mounting metal fitting 140 includes a lower pressing metal fitting 142 and an upper pressing metal fitting 144. Portions of flexible membranes 106 and 108 in the vicinities of the outer peripheral edges thereof are fixed between the lower pressing metal fitting 142 and the upper pressing metal fitting 144 by fastening a nut 144 screwed on an anchor bolt 112 provided at the lower structure 102. As shown in FIG. 18A and FIG. 18B, a plurality of convex portions 146 are formed in the lower pressing metal fitting 142 at intervals, and a plurality of convex portions 148 are formed in the upper pressing metal fitting 144 at intervals. The flexible membranes 106 and 108 are held in a state of being bent by the plurality of convex portions 146 and the plurality of convex portions 148.
In all of the convex portions formed in the conventional mounting metal fitting 100 and in the conventional mounting metal fitting 120, the radius of curvature of the top portion thereof is set to be large. When two or more convex portions are provided in each mounting metal fitting, the respective tops of all of the convex portions are each set at the substantially same radius of curvature.
For this reason, if a tension f acting on the flexible membrane 108 due to expansion increases, the flexible membranes 106 and 108 cannot be supported by the mounting metal fitting. Accordingly, there is a problem in that even if the fastening force is increased, the entire flexible membranes 106 and 108 move slidingly.